Welding Parameter Optimization by Whale Optimization Algorithm and Experimental Investigation on Microstructure and Mechanical Properties of Spin Arc Welded 15CDV6 HSLA Steel

G. Rajesh Kannan,P. Sathiya,T. Deepan Bharathi Kannan,M. Bhuvanesh Kumar 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.9

In this work, the technique of spin arc welding has been used to weld HSLA steel of grade 15CDV6. Experiments wereperformed according to the L9 Taguchi matrix using current, travel speed, wire feed rate, and spin rotation speed as inputparameters. The quality of the weld was analysed by measuring the bead geometry and microhardness. The Whale OptimizationAlgorithm (WOA) was used to identify the optimized welding parameters. The optimised parameters were identifiedthrough WOA as follows: current 230 A, voltage 24 V, travel speed 720 mm/min, and spin rotation speed 1500 rpm. Thepost-weld heat treatment (PWHT) was performed on the optimised welded sample to enhance the weld properties. Themicrohardness was increased by 79% after PWHT. Ferrite content was found to have reduced after welding and PWHT thegrain size and structure of the BM, HAZ, and WM were analysed by EBSD technique. The decrease in ferrite content hada significant effect on the microhardness. The Energy Dispersive Spectroscopy results showed the presence of Vanadiumcarbide (VC) precipitates which helped in increasing the microhardness.

Real world clinical outcomes of adjuvant sequential chemoradiation in patients with gallbladder carcinomas with poor performance status

Rakesh Kapoor,Kannan Periasamy,Rajesh Gupta,Arun Yadav,Divya Khosla 대한방사선종양학회 2020 Radiation Oncology Journal Vol.38 No.4

Purpose: The purpose of the study is to analyze the overall survival, relapse-free survival, and relapse patterns of adjuvant sequential chemoradiation for gallbladder cancers after curative resection in patients with poor performance status. Materials and Methods: We retrospectively reviewed clinical records of gallbladder patients with pathologic stage T2-4 or node positivity treated with sequential chemoradiation at our institute between January 2015 and January 2019. Sequential chemoradiotherapy protocol consisted of six cycles of gemcitabine 1,000 mg/m2 and oxaliplatin 100 mg/m2 administered every 2 weekly and postoperative radiation therapy (45 Gy in 25 fractions over 5 weeks) by three-dimensional conformal technique. Results: A total of 36 patients were included. The median overall survival and relapse-free survival was 26 months (95% confidence interval [CI], 21.4-30.5) and 21 months (95% CI, 11.8-30.1), respectively. The 2-year overall and relapse-free survival rates were 55.1% (95% CI, 37.9%-72.3%) and 44.7% (95% CI, 27.5%-61.9%), respectively. Locoregional, systemic, and combined recurrence were noted in 2 (5.5%), 14 (38.8%), and 3 (8.3%) patients, respectively. On univariate analysis, tumour grading significantly influenced relapse free survival; nodal stage and overall stage demonstrated a statistically significant influence on overall survival (p < 0.05) with a trend towards significance for lymphovascular invasion. On multivariate analysis, no significant factors were found. Grade 3 and 4 haematological adverse events were observed only in 2 (5.5%) with chemotherapy. No grade 3 and 4 adverse events were observed due to radiation therapy. Conclusion: Sequential chemoradiation is feasible and tolerable with acceptable efficacy in the adjuvant setting in patients unfit for concurrent chemoradiotherapy.

Fabrication of Gas Metal Arc Welding Based Wire Plus Arc Additive Manufactured 347 Stainless Steel Structure: Behavioral Analysis Through Experimentation and Finite Element Method

R. Pramod,S. Mohan Kumar,A. Rajesh Kannan,N. Siva Shanmugam,Reza Tangestani 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.1

Wire plus arc additive manufacturing (WAAM) technology is utilized to fabricate a 347 stainless steel (SS347) plate usingthe gas metal arc welding process. The tensile properties of the WAAM plate revealed enhanced strength in comparisonwith the wrought alloy SS347. The microhardness and the ferrite measurement along the building direction (BD) were inthe range of 265–226 HV0.5 and 2.2–5.1 FN (Ferrite number), respectively. The microstructural features were comprehensively examined using electron backscatter difraction (EBSD) analysis and the Inverse pole fgure (IPF) maps revealed astrong <001> texture along the BD. Also, well-aligned equiaxed and columnar dendrites with a lower fraction of niobiumcarbide (NbC) was noticed in the microstructures of the as-built WAAM plate. A three-dimensional fnite element modelwas developed to simulate the build-up of a WAAM plate. Goldak heat source is used to model heat fux in thermal analysis,and the temperature distributions were predicted. Further, residual stress and plastic strain distributions were examined atvarious stages of the WAAM process.

Evaluation of safety and usefulness of submental intubation in panfacial trauma surgery

Mohanavalli Singaram,Ilango Ganesan,Radhika Kannan,Rajesh Kumar 대한구강악안면외과학회 2016 대한구강악안면외과학회지 Vol.42 No.2

Objectives: Submental intubation has been advocated as an alternative to classical tracheostomy for certain indicated panfacial trauma surgeries. Surgeons should have various options for airway management in maxillofacial trauma patients. Most maxillofacial injuries involve occlusal derangements, which might require intraoperative occlusal corrections; hence, orotracheal intubation is not ideal. Maxillofacial surgeons generally prefer nasotracheal intubation; however, in cases with concomitant skull base fracture or nasal bone fracture, nasotracheal intubation might not be suitable; in these situations, tracheostomy is typically performed. However, the possible complications of tracheostomy are well known. Due to trauma situations and to avoid the complications of tracheostomy, submental intubation would be an ideal alternative procedure in selected maxillofacial trauma surgery patients. This study aimed to evaluate the safety and usefulness of a submental intubation technique for panfacial trauma surgery. Moreover, we intended to share our experience of submental intubation and to recommend this simple, safe procedure for certain panfacial trauma surgeries. Materials and Methods: In five panfacial trauma patients, we performed submental intubation for airway management; the mean time required for the procedure was only eight minutes. Results: We were able to execute this procedure safely in a short time without any intraoperative or postoperative complications. Conclusion: Submental intubation is a safe and simple technique for airway management in indicated panfacial trauma surgery patients.

Budd-Chiari syndrome managed with percutaneous recanalization: Long-term outcome and comparison with medical therapy

Chinmay Bhimaji Kulkarni,Srikanth Moorthy,Sreekumar Karumathil Pullara,Nirmal Kumar Prabhu,Ramiah Rajesh Kannan,Puthukudiyil Kader Nazar 소화기인터벤션의학회 2019 International journal of gastrointestinal interven Vol.8 No.2

Background: To compare the outcomes in a group of patients with Budd-Chiari syndrome (BCS) managed by percutaneous recanalization with a group of patients who were managed by medical therapy alone.Methods: We retrieved the hospital records of 37 patients with BCS admitted to our facility between 2004 to 2017 and identified 24 patients (male:female = 10:14; mean age, 32.7 ± 12.5 years) who underwent percutaneous recanalization. Remaining thirteen patients (male:female = 3:10; mean age, 36.77 ± 14.71 years), were managed by medical therapy. Technical and clinical results, complications, and primary patency of percutane-ous recanalization were analyzed. Overall and symptom-free survival rates, the frequency of symptom recurrence, and the number of readmissions for recurrent symptoms were analyzed in both interventional treatment and medical therapy groups.Results: Technical success for recanalization of hepatic vein/inferior venecava by angioplasty ± stenting was achieved in 22 patients (22/24, 91.7%). Clinical success was achieved in 19 patients (19/24, 79.2%). Overall survival for patients who underwent percutaneous recanalization at 1 year and five years was 87.0% and 87.0% and for patients with medical therapy was 90.1% and 45.5%, respectively (P = 0.710). Symptom-free survival for patients who underwent percutaneous recanalization at 1 year and five year was 93.3% and 81.7% and for patients with medical therapy was 26.0% and 0%, respectively (P < 0.001). In the intervention group, 4 patients (4/24, 16.7%) were admitted for recurrent symptoms (median number of read-missions 1, range: 1–2) whereas in medically managed patients 9 patients (9/13, 69.2%) were readmitted (median number of readmissions, 2; range, 1–5) (P = 0.003).Conclusion: There was no statistically significant difference in overall survival of patients managed with percutaneous recanalization and medical therapy. Percutaneous recanalization had definite benefit in terms of fewer recurrent symptoms and hospital admissions, hence should be performed whenever technically feasible.

Endovascular Treatment of Aneurysm of Splenic Artery Arising from Splenomesentric Trunk Using Stent Graft

Chinmay Bhimaji Kulkarni,Srikanth Moorthy,Sreekumar Karumathil Pullara,Rajesh Ramaih Kannan 대한영상의학회 2013 Korean Journal of Radiology Vol.14 No.6

We report a rare case of aneurysm of splenic artery arising anomalously from the superior mesenteric artery (SMA). The aneurysm was treated successfully by coil embolization of the splenic artery distal to aneurysm and then deploying a stent graft in the SMA. A combination of stent graft and coil embolization for the treatment of aberrant splenic artery aneurysm has been reported only once. We describe the imaging findings and the endovascular procedure in this patient.

Budd-Chiari syndrome managed with percutaneous recanalization: Long-term outcome and comparison with medical therapy

Chinmay Bhimaji Kulkarni,Srikanth Moorthy,Sreekumar Karumathil Pullara,Nirmal Kumar Prabhu,Ramiah Rajesh Kannan,Puthukudiyil Kader Nazar 소화기인터벤션의학회 2019 Gastrointestinal Intervention Vol.8 No.2

Background: To compare the outcomes in a group of patients with Budd-Chiari syndrome (BCS) managed by percutaneous recanalization with a group of patients who were managed by medical therapy alone.Methods: We retrieved the hospital records of 37 patients with BCS admitted to our facility between 2004 to 2017 and identified 24 patients (male:female = 10:14; mean age, 32.7 ± 12.5 years) who underwent percutaneous recanalization. Remaining thirteen patients (male:female = 3:10; mean age, 36.77 ± 14.71 years), were managed by medical therapy. Technical and clinical results, complications, and primary patency of percutane-ous recanalization were analyzed. Overall and symptom-free survival rates, the frequency of symptom recurrence, and the number of readmissions for recurrent symptoms were analyzed in both interventional treatment and medical therapy groups.Results: Technical success for recanalization of hepatic vein/inferior venecava by angioplasty ± stenting was achieved in 22 patients (22/24, 91.7%). Clinical success was achieved in 19 patients (19/24, 79.2%). Overall survival for patients who underwent percutaneous recanalization at 1 year and five years was 87.0% and 87.0% and for patients with medical therapy was 90.1% and 45.5%, respectively (P = 0.710). Symptom-free survival for patients who underwent percutaneous recanalization at 1 year and five year was 93.3% and 81.7% and for patients with medical therapy was 26.0% and 0%, respectively (P < 0.001). In the intervention group, 4 patients (4/24, 16.7%) were admitted for recurrent symptoms (median number of read-missions 1, range: 1–2) whereas in medically managed patients 9 patients (9/13, 69.2%) were readmitted (median number of readmissions, 2; range, 1–5) (P = 0.003).Conclusion: There was no statistically significant difference in overall survival of patients managed with percutaneous recanalization and medical therapy. Percutaneous recanalization had definite benefit in terms of fewer recurrent symptoms and hospital admissions, hence should be performed whenever technically feasible.

Prospective evaluation of fiducial marker placement quality and toxicity in liver CyberKnife stereotactic body radiotherapy

Debnarayan Dutta,Kaushik Jagannath Kataki,Shibu George,Sruthi K,Reddy,Ajay Sashidharan,Rajesh Kannan,Ram Madhavan,Haridas Nair,Tushar Tatineni,Raghavendra Holla 대한방사선종양학회 2020 Radiation Oncology Journal Vol.38 No.4

Background: Evaluate morbidities and “quality” of fiducial marker placement in primary liver tumours (hepatocellular carcinoma [HCC]) for CyberKnife. Materials and Methods: Thirty-six HCC with portal vein thrombosis (PVT) were evaluated for “quality” of fiducial placement, placement time, pain score, complications, recovery time and factors influencing placement. Results: One hundred eight fiducials were placed in 36 patients. Fiducial placement radiation oncologist score was “good” in 24 (67%), “fair” in 4 (11%), and “poor” in 3 (8%) patients. Concordance with radiologist score in “poor”, “fair”, and “good” score was 2/2 (100%), 4/5 (80%), and 24/27 (89%), respectively (p=0.001). Child-Pugh score (p=0.080), performance status (PS) (p=0.014) and accrued during “learning curve” (p=0.013) affected placement score. Mean placement time (p=0.055), recovery time (p=0.025) was longer and higher major complications (p=0.009) with poor PS. Liver segment involved (p=0.484) and the Barcelona Clinic Liver Cancer (BCLC) stage did not influence placement score. “Good” placement score was 30% in first cohort whereas 93% in last cohort (p=0.023). Time for placement was 42.2 and 14.3 minutes, respectively (p=0.069). Post-fiducial pain score 0-1 in 26 patients (72%) and pain score 3-4 was in 2 (6%). Five patients (14%) admitted in “day-care” (2 mild pneumothorax, 3 pain). Mortality in 1 patient (3%) admitted for hemothorax. Conclusion: Fiducial placement is safe and in experienced hands, “quality” of placement is “good” in majority. Major complications and admission after fiducial placement are rare. Complications, fiducial placement time, recovery time is more during the “learning curve”. Poor Child-Pugh score, extensive liver involvement, poor PS have higher probability of complications.

Current Status of the Use of Salvaged Blood in Metastatic Spine Tumour Surgery

Naresh Kumar,Nivetha Ravikumar,Joel Yong Hao Tan,Kutbuddin Akbary,Ravish Shammi Patel,Rajesh Kannan 대한척추신경외과학회 2018 Neurospine Vol.15 No.3

To review the current status of salvaged blood transfusion (SBT) in metastatic spine tumour surgery (MSTS), with regard to its safety and efficacy, contraindications, and adverse effects. We also aimed to establish that the safety and adverse event profile of SBT is comparable and at least equal to that of allogeneic blood transfusion. MEDLINE and Scopus were used to search for relevant articles, based on keywords such as “cancer surgery,” “salvaged blood,” and “circulating tumor cells.” We found 159 articles, of which 55 were relevant; 20 of those were excluded because they used other blood conservation techniques in addition to cell salvage. Five articles were manually selected from reference lists. In total, 40 articles were reviewed. There is sufficient evidence of the clinical safety of using salvaged blood in oncological surgery. SBT decreases the risk of postoperative infections and tumour recurrence. However, there are some limitations regarding its clinical applications, as it cannot be employed in cases of sepsis. In this review, we established that earlier studies supported the use of salvaged blood from a cell saver in conjunction with a leukocyte depletion filter (LDF). Furthermore, we highlight the recent emergence of sufficient evidence supporting the use of intraoperative cell salvage without an LDF in MSTS.